Indicator tube



June 16, 1959 1' D. PETERSON ET AL 2,891,185

INDICATOR TUBE Filed Dec. 31, 1957 IN VE N TOR ARTHUR B. SHESSER.

THOMAS D. PETERSON.

ATTORNEY Patented June 16, 1959 United States Patent INDICATOR TUBEThomas D. Peterson, New Market, and Arthur B.

Shesser, Plainfield, N.J., assignors to Burroughs Corporation, Detroit,Mich., a corporation of Michigan Application December 31, 1957, SerialNo. 706,366

8 Claims. (Cl. 313-1095) This invention relates to gaseous indicatortubes.

Gaseous indicator tubes generally comprise a gas-filled envelopeincluding an anode and one or more indicator elements or glow cathodesadapted to glow and provide a visual representation of a number, letter,or the like. Although satisfactory indicator tubes of this type areknown, there is a need for a tube which is comparatively inexpensive,operates on low current and power, may be operated so that either onecathode glows or a plurality of cathodes glow simultaneously, andprovides a visible character or message indication. Accordingly, theobjects of the present invention are to provide a novel and improvedgaseous indicator tube and particularly such a tube which iscomparatively inexpensive, operates on low current and power, and isadapted to display either a single indicator element or a plurality ofindicator elements simultaneously.

In brief, the invention comprises a gaseous glow tube including agas-filled envelope which contains an anode electrode and a plurality ofcathode electrodes adapted to glow when properly electrically energized.The cathode electrodes are essentially rod-like in construction and arearranged in the envelope according to a predetermined pattern. An opaqueshield or plate is provided adjacent to the cathodes and includesperforations which are aligned with the cathode elements. Theperforations are formed in the shape of indicator characters such asnumerals, letters, or the like. Thus, as one or more cathodes areenergied and glow, they may be viewed through the perforations in theshield. The shield may be operated as an anode or a separate anode maybe provided.

The invention is described in greater detail by reference to thedrawing, wherein:

Fig. 1 is a perspective view, partly in section, of an electron tubeembodying the principles of the invention;

Fig. 2 is an exploded view of the tube of Fig. 1; and

Fig. 3 is a perspective view, partly in section, of a modified electrodefor use in the tube of the invention.

Referring to the drawing, a gaseous indicator glow tube embodying theinvention includes an envelope 12 which has been evacuated and filledwith a gas such as neon or the like at a suitable pressure. The envelopeincludes, at one end, a viewing window 14, and, at the other end, a baseportion or stem 16 through which metal base pins 18 extend and by meansof which electrical connection is made to suitable external electricalcircuit elements. The pins 18 are spaced apart about the periphery ofthe stem 16 substantially radially equidistant from the center of thestem and from the longitudinal axis of the tube. The pins 18 extend tosubstantially the same height within the envelope and carry at theirinner ends 19 thin, small-area, metallic apertured disks 20 which aresuitably secured to the pins, for example, by soldering or welding, orthe like. The disks 20 are as large as possible to provide maximum areaof glow without coming into contact with each other. A button 22 ofmaterial having a comparatively low glow threshold, such as molybdenumor the like, is provided at the aperture in each disk 20 and is adaptedto seat on the end 19 of each cathode pin 18. An insulating sleeve 24,for example, of ceramic, glass, or the like, is provided on eachpinbetween the metallic disk 20 and the stem 16 of the envelope. The pins18 are adapted. to be operated as glow cathodes in operation of thetube, with the area of glow of each cathode being determined by the areaof the disk 18 secured thereto.

The tube 10 also includes an anode electrode 25 which includes a thinopaque metal plate or shield 26 oriented transverse to the axis of theenvelope and positioned in shield-like fashion closely adjacent to, butinsulated from, the inner ends 19 of the cathode pins 18. The metalanode plate 26 is placed between the inner ends of the cathode pins andthe viewing window 14 of the envelope 12. The anode 25 also includes aperipheral skirt 27 which extends longitudinally toward the stem 16 andshields the cathode pins 18, and particularly the portions thereof whichglow,from the wall of the envelope. The anode plate 26 is secured to oneor more metal pins 28 which extend through the stem 16. The connectionbetween the pins 28 and plate 24 is made in any suitable fashion, forexample, by means of metal tabs 30 secured to the plate 26 and bonded totabs 31 secured to the pins 28. j

The anode plate 26 is provided with a plurality of perforations 32arrayed about the periphery of the plate, with one perforation alignedwith each cathode pin 18. The perforations are employed as indicatorcharacters and as such are in the form of letters, numbers, or the like.In the tube shown in Fig. 1, the perforations 'are in the form ofnumbers.

If desired, the plate 26 which carries the numeral indieating characters32 may be operated electrically neutral, in which case a separate anode(not shown) is provided in the tube. Such an anode may be in the form ofa rod similar to the pins 18 and 28, or it may be a ring or the like.

'2? and is thus identical to the anode 25, except that it is providedwith a plurality of divider plates 34 which are suitably secured to thelower surface of the plate 26. The divider plates extend radially fromthe center of the plate 26 and terminate adjacent to the skirt 27. Theplates 34 are oriented perpendicular to the plate 26 and extendlongitudinally therefrom and have a width approximately equal to theheight of the skirt 2'7. The divider plates thus divide the anode 25into a plurality of compartments which are isolated from each other. Ina complete tube, each compartment contains a cathode pin and anindicating numeral. Thus, the cathode pins are isolated from each otherand operate independently of each other. In this construction, theinsulating sleeves 24 need not be provided.

It is clear that the cathodes of the tube 10 and the correspondingperforations 32 in the plate 26 may be arranged in any desired fashion;for example, they may be in a linear array rather than the circulararray shown. In addition, the perforations may take any form to providethe desired visible representation.

The tube 10 may be operated in conventional glow tube fashion; that is,when a suitable voltage is provided between a cathode pin and the tubeanode, the cathode pin glows and is visible through the perforation inthe shield plate. One advantage of the present invention is that theoperating voltage may be applied between the anode and more than onecathode simultaneously so that a plurality of cathodes can be caused toglow at the same time. In a typical operating circuit, each cathode ofthe tube 10 draws about 350 microamperes of current at 150 volts. Thisrepresents a power of about .05 watt.

The present invention thus provides an indicator tube which is simple inconstruction, provides flexibility in operation, and is economical tooperate.

What is claimed is:

l. A display tube comprising a gas-filled envelope having a transparentwindow, a plurality of rod-like electrodes oriented parallel to eachother and to the longitudinal axis of said envelope, and a plateorientedbetween the ends of said rods and said window and insulated fromsaid rods, said plate having a plurality of indicator perforations withone perforation aligned with each rod.

2. A display tube comprising a gas-filled envelope having a transparentwindow, a plurality of rod-like glow electrodes oriented parallel toeach other and spaced about the longitudinal axis of said envelope, andan opaque metal plate oriented between said rods and said window andinsulated from said rods, said plate having a plurality of indicatorperforations with one perforation aligned with each rod-like electrodeso that each glowing electrode may be viewed through one of saidperforations.

3. A display tube comprising a gas-filled envelope having a transparentwindow, a plurality of rod-like glow electrodes oriented parallel toeach other and spaced about the longitudinal axis of said envelope, andan opaque metal plate oriented transverse to said axis between said rodsand said window and insulated from said rods, said plate having aplurality of indicator perforations arrayed about the center of saidplate with one perforation aligned with each rod-like electrode so thateach glowing electrode may be viewed through one of said perforations.

4. A display tubecomprising a gas-filled envelope having a transparentwindow, a plurality of rod-like glow electrodes oriented parallel toeach other and spaced about the longitudinal axis of said envelope, andan opaque metal plate oriented transverse to said axis between said rodsand said window and insulated from said rods, said plate having itscenter aligned with the longitudinal axis of said envelope, said platehaving a plurality of indicator perforations arrayed about the center ofsaid plate with one perforation aligned with each rod-like electrode sothat each glowing electrode may be viewed through one of saidperforations.

5. A display tube comprising a gas-filled envelope having a transparentwindow, a plurality of rod-like glow electrodes oriented parallel toeach other and spaced about the longitudinal axis of said envelope, anopaque metal plate oriented transverse to said axis between said rodsand said window and insulated from said rods, said plate having aplurality of indicator perforations with one perforation aligned witheach rod-like electrode so that each glowing electrode may be viewedthrough one of said perforations, and a plurality of divider platessecured to said opaque plate and dividing said plate into a plurality ofcompartments each of which includes a glow electrode.

6. The tube defined in claim 5 wherein said divider plates are securedto the bottom surface of said opaque plate and extend radially from thecenter thereof.

7. A display tube comprising a gas-filled envelope having a transparentwindow, a plurality of rod-like glow electrodes oriented parallel toeach other and spaced about the longitudinal axis of said envelope, asmall metal disk at the end of each of said glow electrodes, and anopaque metal plate oriented transverse to said axis between said rodsand said window and insulated from said rods, said plate having itscenter aligned with the longitudinal axis of said envelope, said platehaving a plurality of indicator perforations arrayed about the center ofsaid plate with one perforation aligned with each rod-like electrode sothat each glowing electrode may be viewed through one of saidperforations.

8. A display tube comprising a gas-filled envelope having a transparentwindow, a plurality of rod-like glowcenter of said plate with oneperforation aligned with each rod-like electrode so that each glowingelectrode may be viewed through one of said perforations.

References Cited in the file of this patent UNITED STATES PATENTS1,560,103 Schmierer -Nov. 3, 1925 2,571,723 Jonker et al. Oct. .16,.1951 2,755,412 Sternbeck July 17, 1956 2,802,130 Engleman et al ..Aug.6, 1957 FOREIGN PATENTS France Apr. 18, 1922;

